Supermarket refrigeration system and associated methods

Abstract

A supermarket refrigeration system may include a plurality of supermarket refrigeration cases, each including an evaporator and an associated compressor connected downstream therefrom. A common condenser is connected downstream from the compressors, and a receiver is connected downstream from the common condenser and upstream from the evaporators. A liquid header extends throughout the supermarket and connects the receiver and the evaporators. A discharge header extends throughout the supermarket and connects the compressors to the common condenser. An oil-bearing refrigerant mixture may circulate through a refrigerant circulation path to lubricate the compressors without undesired pooling and without an oil separator. The system may further include a selectively operable defrost circuit which uses hot refrigerant mixture for defrosting.

1. A supermarket refrigeration system comprising:
 a plurality of supermarket refrigeration cases for containing refrigerated goods therein; 
 each supermarket refrigeration case comprising an evaporator and an associated compressor connected downstream therefrom; 
 a common condenser connected downstream from said compressors; 
 a receiver connected downstream from said common condenser and upstream from said evaporators; 
 a liquid header extending throughout a supermarket and connecting said receiver and said evaporators; 
 a discharge header extending throughout the supermarket and connecting said compressors to said common condenser; and 
 an oil-bearing refrigerant mixture circulating through a refrigerant circulation path defined by said evaporators, compressors, common condenser, receiver, liquid header and discharge header; 
 said oil-bearing refrigerant mixture lubricating said compressors without undesired pooling and without an oil separator in the refrigerant circulation path. 
 
   
   
     2. The supermarket refrigeration system according to  claim 1  wherein said common condenser is located external from the supermarket. 
   
   
     3. The supermarket refrigeration system according to  claim 1  wherein each evaporator and associated compressor have matched capacities. 
   
   
     4. The supermarket refrigeration system according to  claim 1  wherein each supermarket refrigeration case further comprises an insulated enclosure surrounding said compressor. 
   
   
     5. The supermarket refrigeration system according to  claim 1  further comprising at least one unused expansion drop connection along at least one of said liquid header and said discharge header. 
   
   
     6. The supermarket refrigeration system according to  claim 1  wherein each supermarket refrigeration case further comprises a selectively operable defrost circuit to use hot oil-bearing refrigerant mixture for defrosting. 
   
   
     7. The supermarket refrigeration system according to  claim 6  wherein each refrigeration case further comprises a refrigerant defrost pump connected between said evaporator and said liquid header and selectively operable with said defrost circuit. 
   
   
     8. The supermarket refrigeration system according to  claim 1  wherein said common condenser comprises a condenser heat exchanger and a plurality of selectively operable condenser fans associated therewith. 
   
   
     9. The supermarket refrigeration system according to  claim 1  wherein said liquid header and said discharge header each comprises copper lines. 
   
   
     10. The supermarket refrigeration system according to  claim 1  further comprising an expansion valve upstream from said evaporator. 
   
   
     11. A method for operating a supermarket refrigeration system comprising a plurality of supermarket refrigeration cases each comprising an evaporator and an associated compressor connected downstream therefrom, a common condenser connected downstream from the compressors, a receiver connected downstream from the common condenser and upstream from the evaporators, a liquid header extending throughout a supermarket and connecting the receiver and the evaporators, and a discharge header extending throughout the supermarket and connecting the compressors to the common condenser, the method comprising;
 circulating an oil-bearing refrigerant mixture through a refrigerant circulation path defined by the evaporators, compressors, common condenser, receiver, liquid header and discharge header so that the oil-bearing refrigerant mixture lubricates the compressors without undesired, pooling and without an oil separator in the refrigerant circulation path. 
 
   
   
     12. The method according to  claim 11  wherein the common condenser is located external from the supermarket. 
   
   
     13. The method according to  claim 11  wherein each evaporator and associated compressor have matched capacities. 
   
   
     14. The method according to  claim 11  further comprising surrounding each compressor with an insulated enclosure. 
   
   
     15. The method according to  claim 11  further comprising providing at least one unused expansion drop connections along at least one of the liquid header and the discharge header. 
   
   
     16. The method according to  claim 11  wherein each supermarket refrigeration case further comprises a defrost circuit; and further comprising selectively operating the defrost circuit of at least one supermarket refrigeration case to use hot oil-bearing refrigerant mixture for defrosting thereof. 
   
   
     17. The method according to  claim 16  wherein each refrigeration case further comprises a refrigerant defrost pump connected between the evaporator and the liquid header; and further comprising selectively operating. the refrigerant defrost pump with the defrost circuit. 
   
   
     18. The method according to  claim 11  wherein the common condenser comprises a condenser heat exchanger and a plurality of selectively operable condenser fans associated therewith.